Circulating water pump (CWP) is the main power consumption equipment and the cold end optimization is one of the important energy-saving items in fossil fuel power plants. The optimized allocation of CWP with unequal capacity in design stage can obtain a more flexible flow combination in order to meet the required cooling water of unit. By comparing the present energy-saving methods of CWP with the selection of CWP with unequal capacity, the scheme presented in this paper can achieve the energy-saving regulation of CWP, which will bring about a striking energy-saving effect by applying to 2×1 000 MW units.